Avoid strict DM interface version dependencies (#5519)

Compiling against the dm-ioctl.h header as provided by the Linux kernel
will embed the DM interface version number. Running an older kernel can
result in an error like this on shutdown:

Could not detach DM dm-11: ioctl mismatch, kernel(4.34.4), user(4.35.4)

Work around this by shipping a local copy of dm-ioctl.h. We need at
least the version from 3.13 for DM_DEFERRED_REMOVE [1], so bump the
requirements in README accordingly.

[1] https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=2c140a246dc0bc085b98eddde978060fcec1080c

Fixes: #5492

5 files changed, 359 insertions, 3 deletions

diff --git a/Makefile.am b/Makefile.am
index 7ee6c594ca..d4e940c9cf 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -1018,6 +1018,7 @@ libshared_la_SOURCES = \
 	src/shared/gpt.h \
 	src/shared/udev-util.h \
 	src/shared/linux/auto_dev-ioctl.h \
+	src/shared/linux-3.13/dm-ioctl.h \
 	src/shared/initreq.h \
 	src/shared/dns-domain.c \
 	src/shared/dns-domain.h \
diff --git a/README b/README
index a4a6493959..30b5f71876 100644
--- a/README
+++ b/README
@@ -35,7 +35,7 @@ LICENSE:
         - except src/udev/* which is (currently still) GPLv2, GPLv2+
 
 REQUIREMENTS:
-        Linux kernel >= 3.12
+        Linux kernel >= 3.13
         Linux kernel >= 4.2 for unified cgroup hierarchy support
 
         Kernel Config Options:
diff --git a/src/core/umount.c b/src/core/umount.c
index 2f4b12bdb9..454383e7eb 100644
--- a/src/core/umount.c
+++ b/src/core/umount.c
@@ -19,7 +19,6 @@
 
 #include <errno.h>
 #include <fcntl.h>
-#include <linux/dm-ioctl.h>
 #include <linux/loop.h>
 #include <string.h>
 #include <sys/mount.h>
@@ -31,6 +30,7 @@
 #include "escape.h"
 #include "fd-util.h"
 #include "fstab-util.h"
+#include "linux-3.13/dm-ioctl.h"
 #include "list.h"
 #include "mount-setup.h"
 #include "path-util.h"
diff --git a/src/shared/dissect-image.c b/src/shared/dissect-image.c
index 39e724c51a..1c9d21566f 100644
--- a/src/shared/dissect-image.c
+++ b/src/shared/dissect-image.c
@@ -20,7 +20,6 @@
 #ifdef HAVE_LIBCRYPTSETUP
 #include <libcryptsetup.h>
 #endif
-#include <linux/dm-ioctl.h>
 #include <sys/mount.h>
 
 #include "architecture.h"
@@ -32,6 +31,7 @@
 #include "fs-util.h"
 #include "gpt.h"
 #include "hexdecoct.h"
+#include "linux-3.13/dm-ioctl.h"
 #include "mount-util.h"
 #include "path-util.h"
 #include "stat-util.h"
diff --git a/src/shared/linux-3.13/dm-ioctl.h b/src/shared/linux-3.13/dm-ioctl.h
new file mode 100644
index 0000000000..c8a4302093
--- /dev/null
+++ b/src/shared/linux-3.13/dm-ioctl.h
@@ -0,0 +1,355 @@
+/*
+ * Copyright (C) 2001 - 2003 Sistina Software (UK) Limited.
+ * Copyright (C) 2004 - 2009 Red Hat, Inc. All rights reserved.
+ *
+ * This file is released under the LGPL.
+ */
+
+#ifndef _LINUX_DM_IOCTL_V4_H
+#define _LINUX_DM_IOCTL_V4_H
+
+#include <linux/types.h>
+
+#define DM_DIR "mapper"		/* Slashes not supported */
+#define DM_CONTROL_NODE "control"
+#define DM_MAX_TYPE_NAME 16
+#define DM_NAME_LEN 128
+#define DM_UUID_LEN 129
+
+/*
+ * A traditional ioctl interface for the device mapper.
+ *
+ * Each device can have two tables associated with it, an
+ * 'active' table which is the one currently used by io passing
+ * through the device, and an 'inactive' one which is a table
+ * that is being prepared as a replacement for the 'active' one.
+ *
+ * DM_VERSION:
+ * Just get the version information for the ioctl interface.
+ *
+ * DM_REMOVE_ALL:
+ * Remove all dm devices, destroy all tables.  Only really used
+ * for debug.
+ *
+ * DM_LIST_DEVICES:
+ * Get a list of all the dm device names.
+ *
+ * DM_DEV_CREATE:
+ * Create a new device, neither the 'active' or 'inactive' table
+ * slots will be filled.  The device will be in suspended state
+ * after creation, however any io to the device will get errored
+ * since it will be out-of-bounds.
+ *
+ * DM_DEV_REMOVE:
+ * Remove a device, destroy any tables.
+ *
+ * DM_DEV_RENAME:
+ * Rename a device or set its uuid if none was previously supplied.
+ *
+ * DM_SUSPEND:
+ * This performs both suspend and resume, depending which flag is
+ * passed in.
+ * Suspend: This command will not return until all pending io to
+ * the device has completed.  Further io will be deferred until
+ * the device is resumed.
+ * Resume: It is no longer an error to issue this command on an
+ * unsuspended device.  If a table is present in the 'inactive'
+ * slot, it will be moved to the active slot, then the old table
+ * from the active slot will be _destroyed_.  Finally the device
+ * is resumed.
+ *
+ * DM_DEV_STATUS:
+ * Retrieves the status for the table in the 'active' slot.
+ *
+ * DM_DEV_WAIT:
+ * Wait for a significant event to occur to the device.  This
+ * could either be caused by an event triggered by one of the
+ * targets of the table in the 'active' slot, or a table change.
+ *
+ * DM_TABLE_LOAD:
+ * Load a table into the 'inactive' slot for the device.  The
+ * device does _not_ need to be suspended prior to this command.
+ *
+ * DM_TABLE_CLEAR:
+ * Destroy any table in the 'inactive' slot (ie. abort).
+ *
+ * DM_TABLE_DEPS:
+ * Return a set of device dependencies for the 'active' table.
+ *
+ * DM_TABLE_STATUS:
+ * Return the targets status for the 'active' table.
+ *
+ * DM_TARGET_MSG:
+ * Pass a message string to the target at a specific offset of a device.
+ *
+ * DM_DEV_SET_GEOMETRY:
+ * Set the geometry of a device by passing in a string in this format:
+ *
+ * "cylinders heads sectors_per_track start_sector"
+ *
+ * Beware that CHS geometry is nearly obsolete and only provided
+ * for compatibility with dm devices that can be booted by a PC
+ * BIOS.  See struct hd_geometry for range limits.  Also note that
+ * the geometry is erased if the device size changes.
+ */
+
+/*
+ * All ioctl arguments consist of a single chunk of memory, with
+ * this structure at the start.  If a uuid is specified any
+ * lookup (eg. for a DM_INFO) will be done on that, *not* the
+ * name.
+ */
+struct dm_ioctl {
+	/*
+	 * The version number is made up of three parts:
+	 * major - no backward or forward compatibility,
+	 * minor - only backwards compatible,
+	 * patch - both backwards and forwards compatible.
+	 *
+	 * All clients of the ioctl interface should fill in the
+	 * version number of the interface that they were
+	 * compiled with.
+	 *
+	 * All recognised ioctl commands (ie. those that don't
+	 * return -ENOTTY) fill out this field, even if the
+	 * command failed.
+	 */
+	__u32 version[3];	/* in/out */
+	__u32 data_size;	/* total size of data passed in
+				 * including this struct */
+
+	__u32 data_start;	/* offset to start of data
+				 * relative to start of this struct */
+
+	__u32 target_count;	/* in/out */
+	__s32 open_count;	/* out */
+	__u32 flags;		/* in/out */
+
+	/*
+	 * event_nr holds either the event number (input and output) or the
+	 * udev cookie value (input only).
+	 * The DM_DEV_WAIT ioctl takes an event number as input.
+	 * The DM_SUSPEND, DM_DEV_REMOVE and DM_DEV_RENAME ioctls
+	 * use the field as a cookie to return in the DM_COOKIE
+	 * variable with the uevents they issue.
+	 * For output, the ioctls return the event number, not the cookie.
+	 */
+	__u32 event_nr;      	/* in/out */
+	__u32 padding;
+
+	__u64 dev;		/* in/out */
+
+	char name[DM_NAME_LEN];	/* device name */
+	char uuid[DM_UUID_LEN];	/* unique identifier for
+				 * the block device */
+	char data[7];		/* padding or data */
+};
+
+/*
+ * Used to specify tables.  These structures appear after the
+ * dm_ioctl.
+ */
+struct dm_target_spec {
+	__u64 sector_start;
+	__u64 length;
+	__s32 status;		/* used when reading from kernel only */
+
+	/*
+	 * Location of the next dm_target_spec.
+	 * - When specifying targets on a DM_TABLE_LOAD command, this value is
+	 *   the number of bytes from the start of the "current" dm_target_spec
+	 *   to the start of the "next" dm_target_spec.
+	 * - When retrieving targets on a DM_TABLE_STATUS command, this value
+	 *   is the number of bytes from the start of the first dm_target_spec
+	 *   (that follows the dm_ioctl struct) to the start of the "next"
+	 *   dm_target_spec.
+	 */
+	__u32 next;
+
+	char target_type[DM_MAX_TYPE_NAME];
+
+	/*
+	 * Parameter string starts immediately after this object.
+	 * Be careful to add padding after string to ensure correct
+	 * alignment of subsequent dm_target_spec.
+	 */
+};
+
+/*
+ * Used to retrieve the target dependencies.
+ */
+struct dm_target_deps {
+	__u32 count;	/* Array size */
+	__u32 padding;	/* unused */
+	__u64 dev[0];	/* out */
+};
+
+/*
+ * Used to get a list of all dm devices.
+ */
+struct dm_name_list {
+	__u64 dev;
+	__u32 next;		/* offset to the next record from
+				   the _start_ of this */
+	char name[0];
+};
+
+/*
+ * Used to retrieve the target versions
+ */
+struct dm_target_versions {
+        __u32 next;
+        __u32 version[3];
+
+        char name[0];
+};
+
+/*
+ * Used to pass message to a target
+ */
+struct dm_target_msg {
+	__u64 sector;	/* Device sector */
+
+	char message[0];
+};
+
+/*
+ * If you change this make sure you make the corresponding change
+ * to dm-ioctl.c:lookup_ioctl()
+ */
+enum {
+	/* Top level cmds */
+	DM_VERSION_CMD = 0,
+	DM_REMOVE_ALL_CMD,
+	DM_LIST_DEVICES_CMD,
+
+	/* device level cmds */
+	DM_DEV_CREATE_CMD,
+	DM_DEV_REMOVE_CMD,
+	DM_DEV_RENAME_CMD,
+	DM_DEV_SUSPEND_CMD,
+	DM_DEV_STATUS_CMD,
+	DM_DEV_WAIT_CMD,
+
+	/* Table level cmds */
+	DM_TABLE_LOAD_CMD,
+	DM_TABLE_CLEAR_CMD,
+	DM_TABLE_DEPS_CMD,
+	DM_TABLE_STATUS_CMD,
+
+	/* Added later */
+	DM_LIST_VERSIONS_CMD,
+	DM_TARGET_MSG_CMD,
+	DM_DEV_SET_GEOMETRY_CMD
+};
+
+#define DM_IOCTL 0xfd
+
+#define DM_VERSION       _IOWR(DM_IOCTL, DM_VERSION_CMD, struct dm_ioctl)
+#define DM_REMOVE_ALL    _IOWR(DM_IOCTL, DM_REMOVE_ALL_CMD, struct dm_ioctl)
+#define DM_LIST_DEVICES  _IOWR(DM_IOCTL, DM_LIST_DEVICES_CMD, struct dm_ioctl)
+
+#define DM_DEV_CREATE    _IOWR(DM_IOCTL, DM_DEV_CREATE_CMD, struct dm_ioctl)
+#define DM_DEV_REMOVE    _IOWR(DM_IOCTL, DM_DEV_REMOVE_CMD, struct dm_ioctl)
+#define DM_DEV_RENAME    _IOWR(DM_IOCTL, DM_DEV_RENAME_CMD, struct dm_ioctl)
+#define DM_DEV_SUSPEND   _IOWR(DM_IOCTL, DM_DEV_SUSPEND_CMD, struct dm_ioctl)
+#define DM_DEV_STATUS    _IOWR(DM_IOCTL, DM_DEV_STATUS_CMD, struct dm_ioctl)
+#define DM_DEV_WAIT      _IOWR(DM_IOCTL, DM_DEV_WAIT_CMD, struct dm_ioctl)
+
+#define DM_TABLE_LOAD    _IOWR(DM_IOCTL, DM_TABLE_LOAD_CMD, struct dm_ioctl)
+#define DM_TABLE_CLEAR   _IOWR(DM_IOCTL, DM_TABLE_CLEAR_CMD, struct dm_ioctl)
+#define DM_TABLE_DEPS    _IOWR(DM_IOCTL, DM_TABLE_DEPS_CMD, struct dm_ioctl)
+#define DM_TABLE_STATUS  _IOWR(DM_IOCTL, DM_TABLE_STATUS_CMD, struct dm_ioctl)
+
+#define DM_LIST_VERSIONS _IOWR(DM_IOCTL, DM_LIST_VERSIONS_CMD, struct dm_ioctl)
+
+#define DM_TARGET_MSG	 _IOWR(DM_IOCTL, DM_TARGET_MSG_CMD, struct dm_ioctl)
+#define DM_DEV_SET_GEOMETRY	_IOWR(DM_IOCTL, DM_DEV_SET_GEOMETRY_CMD, struct dm_ioctl)
+
+#define DM_VERSION_MAJOR	4
+#define DM_VERSION_MINOR	27
+#define DM_VERSION_PATCHLEVEL	0
+#define DM_VERSION_EXTRA	"-ioctl (2013-10-30)"
+
+/* Status bits */
+#define DM_READONLY_FLAG	(1 << 0) /* In/Out */
+#define DM_SUSPEND_FLAG		(1 << 1) /* In/Out */
+#define DM_PERSISTENT_DEV_FLAG	(1 << 3) /* In */
+
+/*
+ * Flag passed into ioctl STATUS command to get table information
+ * rather than current status.
+ */
+#define DM_STATUS_TABLE_FLAG	(1 << 4) /* In */
+
+/*
+ * Flags that indicate whether a table is present in either of
+ * the two table slots that a device has.
+ */
+#define DM_ACTIVE_PRESENT_FLAG   (1 << 5) /* Out */
+#define DM_INACTIVE_PRESENT_FLAG (1 << 6) /* Out */
+
+/*
+ * Indicates that the buffer passed in wasn't big enough for the
+ * results.
+ */
+#define DM_BUFFER_FULL_FLAG	(1 << 8) /* Out */
+
+/*
+ * This flag is now ignored.
+ */
+#define DM_SKIP_BDGET_FLAG	(1 << 9) /* In */
+
+/*
+ * Set this to avoid attempting to freeze any filesystem when suspending.
+ */
+#define DM_SKIP_LOCKFS_FLAG	(1 << 10) /* In */
+
+/*
+ * Set this to suspend without flushing queued ios.
+ * Also disables flushing uncommitted changes in the thin target before
+ * generating statistics for DM_TABLE_STATUS and DM_DEV_WAIT.
+ */
+#define DM_NOFLUSH_FLAG		(1 << 11) /* In */
+
+/*
+ * If set, any table information returned will relate to the inactive
+ * table instead of the live one.  Always check DM_INACTIVE_PRESENT_FLAG
+ * is set before using the data returned.
+ */
+#define DM_QUERY_INACTIVE_TABLE_FLAG	(1 << 12) /* In */
+
+/*
+ * If set, a uevent was generated for which the caller may need to wait.
+ */
+#define DM_UEVENT_GENERATED_FLAG	(1 << 13) /* Out */
+
+/*
+ * If set, rename changes the uuid not the name.  Only permitted
+ * if no uuid was previously supplied: an existing uuid cannot be changed.
+ */
+#define DM_UUID_FLAG			(1 << 14) /* In */
+
+/*
+ * If set, all buffers are wiped after use. Use when sending
+ * or requesting sensitive data such as an encryption key.
+ */
+#define DM_SECURE_DATA_FLAG		(1 << 15) /* In */
+
+/*
+ * If set, a message generated output data.
+ */
+#define DM_DATA_OUT_FLAG		(1 << 16) /* Out */
+
+/*
+ * If set with DM_DEV_REMOVE or DM_REMOVE_ALL this indicates that if
+ * the device cannot be removed immediately because it is still in use
+ * it should instead be scheduled for removal when it gets closed.
+ *
+ * On return from DM_DEV_REMOVE, DM_DEV_STATUS or other ioctls, this
+ * flag indicates that the device is scheduled to be removed when it
+ * gets closed.
+ */
+#define DM_DEFERRED_REMOVE		(1 << 17) /* In/Out */
+
+#endif				/* _LINUX_DM_IOCTL_H */